Lubricant



Patented Apr. 6, 1943 UNITED STATES LUBRICANT James W. Gaynor, Chicago, 111., and Clarence M. Loanc, Hammond, Ind., assignors to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Application June 26, 1941, Serial No. 399,936

21 Claims. (01. 252-48) The present invention relates to improvements in additives for lubricating oils, and in particular to an improved phosphorus and sulfur-containing additive for lubricating oils and to the meth- .od of preparing the same.

The present' invention further relates to lubricants containing t e improved additive. These lubricants are particularly adapted for use in internal combustion engines such as spark-ignition internal combustion engines, and compression-ignition internal combustion engines, which operate under severe conditions wherein corrosion, piston ring sticking, sludge, cylinder wear, carbon and varnish formation may be encountered.

Straight petroleum lubricants are effective within certain defined limits of engine operating conditions and when these limits are exceeded such lubricants frequently fail to give the desired performance demanded of them. Since in modern engines designed to give increased performance these limits are frequently exceeded, the use of straight mineral oils as lubricants in such engines produces undesirable conditions, such as excessive sludge, varnish, carbon formation, and corrosion of improved hard metal alloy bearings, which may be employed in such engines.

It is an object of the present invention to provide for internal combustion engines a lubricant which will be effective in providing adequate lubrication for such engines. It is a further object of the invention to provide a lubricant which Will not be conducive to the formation of sludge and/or varnish and/ or carbon. Another object of the invention is to provide a lubricant which will reduce engine wear and be non-corrosive to bearings. It is another object of the present invention to provide an additive for lubricants which will inhibit the formation of sludge and/or carbon in lubricants to which it is added and further, which will inhibit corrosion and reduce engine wear. Other objects and advantages of the present invention will become apparent as the description thereof proceeds.

In co-pending applications Serial No. 384,942 filed March 24, 1941, and Serial No. 384,943 filed March 24, 1941, of which the present application is a continuation-in-part, there are respectively described improved methods of preparing phosphorus sulfide-hydrocarbon reaction products and phosphorus sulfide-olefin polymer reaction products as additives to mineral oils. ventions of the aforesaid applications relate to treating such reaction products at about 100 F. to about 600 F. with an agent having an active hydrogen atom such as for example, steam, in order to improve the odor thereof. While such treatment effectively eliminates the odor of these reaction products the treatment results in a decrease in the sulfur content of the final product.

We have now discovered an improved method The inof preparing phosphorus sulfide-hydrocarbon and/or olefin polymer reaction products which are substantially free of objectionable odors and which have a substantial sulfur content. In accordance with the present invention, the improvement comprises introducing sulfur into the phosphorus sulfide-olefin polymer or other phosphorus sulfide-hydrocarbon reaction products by means of sulfurization. The sulfurization may take place prior to or subsequent to the phosphorus sulfide reaction but preferably simultaneously with the latter. The product so obtained, either undiluted or in solution in hexane or other suitable solvents, may then be treated at elevated temperatures from about 100 F. to about 600 F. and preferably from about 300 F. to about 450 F., preferably in a non-oxidizing atmosphere with an agent having an active hydrogen atom. Illustrative of the type of agents which have an active hydrogen atom at elevated temperatures and which are well suited for the hereindescribed purpose are steam, alcohols, ammonia and amines.

As starting materials for the production of the phosphorus sulfide-olefin polymer reaction products, are the polymers of olefinic hydrocarbons, particularly polymers of low molecular weight mono-olefinic hydrocarbons.

The mono-olefin polymers to be treated are suitably the polymers resulting from the polymerization of low molecular weight iso-mono-olefins such as isobutylene, isoamylene, etc. and/or the co-polymers obtained by the polymerization of hydrocarbon mixtures containing low molecular iso-mono-olefins, preferably together with normal mono-olefins such as those of less than six car n atoms, and preferably those of four carbon atoms. The polymer can be obtained by the polymerization of these mono-olefins or mixed mono-clefins in the presence of a catalyst such as sulfuric acid, phosphoric acid, boron fluoride, aluminum chloride or other similar halide catalyst of the Friedel-Crafts type.

The polymers employed are preferably monoolefin polymers, in which the molecular weight ranges from about 150 to about 50,000, or more, and preferably from about 500 to about 10,000. These polymers can be obtained, for example, by the polymerization in the liquid phase of isoolefins such as isobutylene or hydrocarbon mixtures containing the same at a temperature of from about F. to about F., in the presence of a catalyst such as boron fluoride. In the preparation of these polymers we may employ, for example, liquid isobutylene or a hydrocarbon mixture containing isobutylene, butanes, and butylene, recovered from petroleum gases, especially those gases produced in the cracking of petroleum oils in the manufacture of gasoline. This light fraction may contain from about 10% to cipally butanes and normal butylene.

The preparation of low molecular weight polymers having molecular weights varying from about 150 to about 2,000, from the butane-butylene-isobutylene fraction can be carried out as follows: The hydrocarbon mixture containing 10% to 25% isobutylene is maintained under pressure sufficient to keep it in the liquid phase and cooled to a temperature of, for example, from about F. to about 100 F. and preferably from about 0 F. to about 32 F. and from about 0.1% to about 2% boron fluoride, based upon the isobutylene content of the material treated, is added with vigorous agitation. Excessive rise in the temperature due to the heat of reaction can be avoided by efficient cooling. After the polymerization of the isobutylene together with a relatively minor amount of the normal olefins present, the reaction mass is neutralized and washed free of acidic substances arising from the catalyst, the oily layer is separated, and the polymer subsequently separated from the unreacted hydrocarbons by distillation. The polymer mixture so obtained, depending upon the temperature of reaction, varies in consistency from a light liquid to a viscous oily material and contains polymers having molecular weights ranging from about 116 to 2,000. The polymers so obtained may be fractionated under reduced pressure into fractions of increasing molecular weights, for example, a distillate of about 150 seconds to about 200 seconds Saybolt Universal viscosity at 100 F., or other desired fractions, and the fractions, or any one of them, used as a starting material. The bottoms resulting from the distillation of the polymer are well suited for the purpose of the present invention. Bottoms having Saybolt Universal viscosities at 210 F. of from about 50 seconds to about 10,000 seconds, and preferably above 80 seconds can be employed.

Other hydrocarbons which we can use as reactants in the preparation of the phosphorus sulfide reaction product are paraflins, olefins, aromatics or alkyl aromatics, cyclic aliphatics, petroleum fractions, such as lubricating oil fractions, petrolatums, waxes, cracking cycle stocks, condensation products of petroleum fractions, solvent extracts of petroleum extracts, etc.

The paraffin hydrocarbons can be those obtained from petroleum oils such as bright stock residuums, lubricating oil distillates, petrolatums, or paraffin waxes. We may also halogenate any of the foregoing paraflins and condense the same with aromatic hydrocarbons in the presence of anhydrous inorganic halides such as aluminum chloride, zinc chloride, boron fluoride and the like.

As examples of high molecular weight olefinic hydrocarbons which we may employ as reactants are cetene (Cm) cerotene (C26) melene (Cao) and mixed high molecular weight alkenes obtained by cracking petroleum oils.

Another class of compounds which may be used as starting materials are the aromatic hydrocarbons such as for example, benzene, naphthalene, toluene, xylene, diphenyl and the like, or alkylated aromatic hydrocarbons such as, for example, alkyl substituted benzene, alkyl substituted naphthalene, and the like in which the alkyl radical has at least four carbon atoms and in which the alkyl radical is preferably a long-chain radical such as paraffin wax.

In the preparation of our improved additive, the hydrocarbon constituent may be sulfurized prior to, or subsequent to, the reaction with the I about 25% isobutylene, the remainder being prinphosphorus sulfide, although we prefer to sulfurize simultaneously with the reaction with phosphorus sulfide. When the sulfurization takes place prior to or subsequent to the treatment with the phosphorus sulfide it can be accomplished by treating the hydrocarbon or phosphorus-sulfide hydrocarbon reaction product respectively with elemental sulfur at a temperature of from about 250 F. to about 450 F. and preferably at a temperature from about 350 F. to about 375 F. We can also accomplish the sulfurization with a sulfur halide such as sulfur chloride in which case the sulfurization can be carried out at somewhat lower temperatures.

The phosphorus sulfide-hydrocarbon reaction product may be obtained by reacting a phosphorus sulfide such as, for example, P283, P481, P4S3, and preferably PzSs, with any of the above described hydrocarbons at temperatures of from about 200 F. to about 500 F. and preferably from about 300 F. to about 400 F. The reaction is preferably carried out in a non-oxidizing atmosphere, such as an atmosphere of nitrogen.

From about 1% to about 50% and preferably from about 5% to about 25% of the phosphorus sulfide can be used. If an excess of the phosphorus sulfide is used the reaction product may be freed of the excess phosphorus sulfide by filtering or by diluting with a solvent such as hexane and filtering and subsequently removing the diluent.

The phosphorus sulfide-hydrocarbon reaction product as above obtained normally shows a titratable acidity which is neutralized when the reaction product is treated with a basic reagent. When the neutralization is carried out with a basic reagent having a metal constituent the neutralized product is characterized by the presence or retention of the metal constituent of the reagent. Other metal constituents may be introduced into the neutralization product by reacting the same with a salt of the desired heavy metal.

The term neutralized phosphorus sulfide-hydrocarbon reaction product" as used herein means a phosphorus sulfide-hydrocarbon reaction product having at least about 1% of its titratable acidity reduced by the reaction with a basic reagent and includes the neutralized phosphorus sulfide-hydrocarbon reaction products containing a metal constituent resulting from said neutralization or resulting from the reaction of a heavy metal salt with the phosphorus sulfidehydrocarbon reaction product treated with a basic reagent.

The phosphorus sulfide-hydrocarbon reaction product or the sulfurized-phosphorus sulfide-hydrocarbon reaction product may be neutralized by treating the reaction product with a suitable basic compound such as a hydroxide, a carbonate, or an oxide of an alkaline earth metal or an alkali metal, preferably calcium oxide, potassium hydroxide, or sodium hydroxide. Other basic reagents. may be used such as, for example, ammonia or an alkyl or aryl substituted ammonia, such as amines. The neutralization may be carried out in a non-oxidizing atmosphere. As aforesaid when the reaction product is neutralized with a basic compound having a metal constituent the neutralized product is characterized by the presence of the metal constituent of the basic reagent. Neutralized reaction products containing a heavy metal constituent such as, for example, tin, titanium, aluminum, chromium, cobalt, iron and the like, may be obtained by reacting a salt of the desired heavy metal with the reaction products which have been treated with a basic reagent. When the neutralization is accomplished with a polyvalent basic metal, such as lime, a product having excess basicity may be obtained.

The neutralization of the titratable acidity may take place subsequent to sulfurization and reaction with the phosphorus sulfide, or the phosphorus sulfide reaction product may be neutralized and the neutralized product subsequently treated with sulfur, although the former procedure is preferred.

The following examples re set forth as illustrative of the present inven ion and it is not our intention thereby to limit the scope of the invention to the examples given.

EXAMPLE I An olefin polymer having a Saybolt Universal viscosity at 210 F. of 83 seconds, prepared by polymerizing a mixture of butylenes and isobutylene in the presence of boron fluoride, was sulfurized with sulfur for 72 hours at a temperature of 341 F. Air. was bubbled through the reactants at a ,rate of 10 liters per hour to promote oxidation and to insure intimate contact of the sulfur'and the polymer. The final reaction product was diluted with two volumes of hexane, settled at 10 F. for hours, filtered to remove unreacted sulfur and the hexane subsequently removed from the filtrate by evaporation on a steam bath. The sulfurized product contained 6.16% sulfur.

This sulfurized polymer oil was then reacted with 10% P285 for 6 hours at a temperature of 370 to 380 F. during which time nitrogen was bubbled through the reaction mixture. This reaction product was then neutralized with 9% solid KOH at a temperature of 370 F. to 380 F. and then blown with nitrogen for an additional two hours within the same temperature range. The neutralized product had a phosphorus content of 2.09%, a sulfur content of 3.75% and a potassium content of 5.89%. The product after being blown with steam for about four hours at a temperature of from about 360 F. to about 370 F. had a sulfur content of about 1.7% and a phosphorus and potassium content substantially the same as above.

EXAMPLE II An isobutylene polymer, having a Saybolt Universal viscosity at 210 F. of about 3,000 seconds, obtained by polymerizing in the presence of boron fluoride a hydrocarbon mixture containing from about 10% to about isobutylene was reacted simultaneously with 10% phosphorus pentasulfide and 3% sulfur for five hours at 370 F. to 380 F. and then blown for an additional three hours with nitrogen Within the same temperature range. This product had a phosphorus content of 2.6% and a sulfur content of 6%.

EXAMPLE III EXAMPLE IV A portion of the nitrogen blown neutralized product of Example III was blown with steam for four hours at 360 F. to 370 F. The final resulting product was clear, free of any hydrogen sulfide odor, and possessed an unobjectionable mild odor typical of sulfurized oils. This product had a phosphorus content of 2.6%, a sulfur content of-1.76% and a potassium content of 3%. The analyses of this product show that it contained stable sulfur which is not removed by the drastic steam treatment.

The eifectiveness of the deodorized sulfurized PzSs-olefin polymer reaction products in improving the stability of lubricating oils is demonstrated by a test described as follows: 250 cc. of the oil to be tested is heated at 330 F. to 332 F. in a. 500 cc. glass beaker in the presence of five square inches of copper and ten square inches of iron. Four glass rods of six millimeter diameter are suspended in the oil which is stirred at about 1300 R. P. M. with a glass stirrer having a 40 blade pitch. At stated intervals oil samples are taken and the sludge, acidity and viscosity values determined. The glass rods are also inspected for evidence of varnish formation thereon. Varnish values are based on a visual rating in which a glass rod free of any varnish is given a rating of 10 while a heavily coated rod is given a rating of 1, and a rod having a coating between these extremes is given an intermediate value between 1 and 10 The following oils were subjected to the above test:

TABLE I of the product of Example II of the product of Example IV i l i Sludge Acidity max/l0 g. oil mg. KOH/g. oil

92 24 I 48 72 92 24 4X 72 92 hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs.

Varnish Oil 24 hrs.

48 hrs.

72 hrs.

The above data show the effectiveness of our improved additive in inhibiting the formation of sludge and acidity in lubricating oils and in preventing the development of varnish forming bodies in lubricants.

The effectiveness of the hereindescribed additive in inhibiting corrosion to alloy bearings, particularly lead-containing alloy bearings is demonstrated by the following data shown in Table II. These data are obtained by placing strips of copper lead bearings and small lead strips in samples of motor oils with and without the inhibitor added thereto. and maintaining the oil at a temperature of about 330 F. The test is carricd out by placing 250 cc. of the oil to be tested in a 500 cc. glass beaker in which the test strips are suspended and heating the oil to a temperature of 330 F. to 332 F. while agitating the oil by means of a mechanical stirrer. At intervals the strips are removed from the oil, washed and weighed and the loss in weight determined. After each determination of the corrosion loss the strips are polished and reweighed before being replaced in the oil. The strips used in the test hereindescribed had a surface area of about '1 square centimeters. The data tabulated in Table II were obtained with the following oils:

TABLE II Lead corrosion lss-mgs./strip M Ti 11-1 1-2 2c 3-4 4-20 8g I hour hours hours hours hours 040 l 1 l i i l 011 A. 1 l 0,11 11.1 14.0 3911i are; war one... 0.0 0.3 1.1 2.2 47 50.0 0110... 0.2 11.4 (in 1.0. an 55.2

The above data clearly show the corrosion inhibiting effect of the hereindescribed addition agent.

While we have described the use of the sulfurized-phosphorus sulfide-hydrocarbon reaction product in lubricating oils for which use the reaction product may be employed in amounts of from about 0.001% to about 10% and preferably from about 0.01% to about 3%, our invention is not limited to such use since these reaction products may be used in other petroleum products such as insulating oils, white oils, greases, waxes, etc.

The reaction product per se made according to this invention, and the process of preparing same are claimed in a copending application.

Although we have described preferred embodiments of our invention other modifications may be used without departing from the scope and spirit of the invention and we do not wish to limit our invention to the specific example set forth herein except insofar as the same is defined by the following claims.

We claim:

1. A lubricant containing a lubricating oil and a minor amount of the phosphorus and sulfurcontaining product obtained by the process comprising reacting a hydrocarbon with a sulfurizing agent and a phosphorus sulfide, and subsequently reacting the product so obtained with a basic reagent.

2. A lubricant containing a lubricating oil and a minor amount of the phosphorus and sulfurcontaining product obtained by the process comprising reacting an olefin polymer with sulfur and a phosphorus sulfide treating the reaction product with a basic reagent, and subsequently treating the neutralized reaction product at a temperature of from about 100 F. to about 600 F. with an agent having an active hydrogen atom.

3. A lubricant containing a lubricating oil and a minor amount of the phosphorus and sulfurcontaining product obtained by the process comprising reacting an isobutylene polymer with a sulfurizing agent and a phosphorus sulfide, treating the reaction product with a basic reagent, and subsequently blowing the neutralized reaction product with steam at a temperature of from about 300 F. to about 400 F. until the product is substantially free of hydrogen sulfide.

4. A new composition comprising a hydrocarbon oil and a phosphorus and sulfur-containing product obtained by the process comprising reacting a hydrocarbon with a sulfurizing agent and a phosphorus sulfide and subsequently treating the reaction product with a basic reagent.

5. A new composition comprising a hydrocarbon oil and the metal-containing and phosphorus and sulfur-containing product obtained by the process comprising reacting a hydrocarbon with a sulfurlzing agent and a phosphorus sulfide and treating the reaction product with a basic reagent containing a metal constituent.

6. A new composition comprising a hydrocarbon oil and the neutralized phosphorus and sulfur-containing product obtained by the process comprising reacting an olefin polymer with a sulfurizing agent and a phosphorus sulfide, and treating the reaction product with a basic reagent.

7. A new composition comprising a hydrocarbon oil and the metal-containing and phosphorus and sulfur-containing product obtained by the process comprising reacting an olefin polymer with a sulfurizing agent and a phosphorus sulfide and then treating the reaction product with a basic reagent containing a metal constituent.

8. A new composition as described in claim 7 in which the metal is an alkali metal.

. 9. A new composition as described in claim '1 in which the metal is potassium.

10. A new composition as described in claim 7 in which the metal is sodium.

v11. A new composition as described in claim 7 in which the metal is an alkaline earth metal.

12. A new composition as decribed in claim 7 in which the metal is calcium.

13. A new composition as described in claim 7 in which the olefin polymer is a mono-olefin polymer, the sulfurizing agent is elemental sulfur and the phosphorus sulfide is phosphorus pentasulfide.

14. A new composition comprising a hydrocarbon oil and the phosphorus and sulfur-containing product obtained by the process comprising simultaneously reacting an olefin polymer with sulfur and a phosphorus sulfide and treating the reaction product with a basic reagent.

15. A new composition comprising a hydrocarbon oil and the phosphorus and sulfur-containing product obtained by the process comprising reacting an olefin polymer with a sulfurizing agent and a phosphorus sulfide, neutralizing the reaction product with a basic reagent and blowing with an agent having an active hydrogen atom at a temperature of from about F. to about 600 F.

16. A lubricant containing a lubricating oil and a small amount of the metal-containing and phosphorus and sulfur-containing product obtained by the process comprising reacting an olefin polymer with a sulfurizing agent and a phosphorus sulfide and treating the reaction product with a basic reagent containing a. metal constituent.

17. A lubricant as described in claim which the metal is an alkali metal.

18. A lubricant as described in claim which the metal is potassium.

19. A lubricant as described in claim which the metal is sodium.

20. A lubricant as described in claim 16 in which the metal is an alkaline earth metal.

21. A lubricant as described in claim 16 in which the metal is calcium.

JAMES W. GAYNOR. CLARENCE M. LOANE. 

